An interface device for implantation in a subject includes a tissue integration layer and a crowning element. The tissue integration layer has a porous structure adapted for ingress of tissue to anchor the device when implanted. The crowning element is adapted for epidermal attachment when the device is implanted and is configured such that once implanted, part of the crowning element extends through the epidermis and is accessible from outside the subject's body. The porous structure of the tissue integration layer is interconnected for tissue ingress during implantation.